This application is related to Japanese Patent Application No. 2000-123268 filed on Apr. 24, 2000, whose priority is claimed under 35 USC xc2xa7119, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a method of bonding a tubulation tubing of a display panel, more particularly, a method of bonding a tubulation tubing to a display panel such as a plasma display panel (PDP) for removing an impurity gas from an electric discharge space in the display panel and introducing an electric discharge gas into the discharge space.
2. Description of Related Art
In a display panel such as a PDP, the discharge space is usually formed in the panel by disposing a front substrate and a back substrate of the panel opposedly and sealing the peripheries of the substrates together. Typically, in the production of the panel, a vent hole is opened in the back substrate and a glass tubulation tubing is bonded to the perimeter of the vent hole when the front and back substrates are sealed together. Via this tubulation tubing, the impurity gas is removed from the inside of the panel and the discharge gas is fed in the panel. Thereafter, the tubulation tubing is cut by fusing (melting) so that a tubulation path in the tubulation tubing is closed, thereby making the discharge space air-tight.
In order to bond the tubulation tubing to the back substrate, usually, a glass frit or glass powder is mixed with a binder and formed in a ring shape. This glass material (also referred to as a sealing glass) is preliminarily baked to release gas therefrom and placed between a flare edge of the tubulation tubing and the back substrate. The glass material is fastened provisionally with the tubulation tubing by means of a clip. Thereafter a sealing step is conducted for sealing the front substrate and the back substrate together (by fusing a sealing member with heat), thereby also welding the tubulation tubing to the back substrate with the glass material.
However, since the glass material is between the flare end portion of the tubulation tubing and the back substrate, the glass material, melted, may enter the inside of the tubulation tubing and block the tubulation tubing when the tubulation tubing and the back substrate are bonded by melting the glass material. The melted glass material may also enter the inside of the panel when the impurity gas is vented out and the discharge gas is fed into the panel.
Where the sealing step is carried out after the glass material has been provisionally fastened together with the tubulation tubing by a clip, the glass material softened in the sealing step is pushed out from between the flare end portion of the tubulation tubing and the back substrate and adheres to the clip. As a result, it may become difficult to remove the glass material when the clip is taken off or the glass material may crack when removed.
Further, if the pressing force by the clip for holding the tubulation tubing is too strong, the glass member is pushed out from the flare end portion of the tubulation tubing. For this reason, the pressing force cannot be strengthened above a certain degree. Therefore, when the sealing step is carried out with the glass material being provisionally fastened together with the tubulation tubing by the clip, the tubulation tubing may possibly be inclined when a little force is applied.
In these circumstances, the present invention is intended to provide a method of bonding a tubulation tubing of a display panel which can prevent the entry of the adhesive member into the tubulation tubing or the adhesion of the adhesive member to the clip, by preparing a tubulation tubing having a flange with a substantially flat end face and an adhesive member to be fitted to the perimeter of the flange of the tubulation tubing, placing the tubulation tubing and the adhesive member at a vent hole of a display panel, and pressing the flange against the display panel with a clip to bond the tubulation tubing to the display panel.
The present invention provides a method of bonding a tubulation tubing of a display panel comprising the steps of: preparing a tubular tubulation tubing having, at one end, a flange with a substantially flat end face and a ring-shape adhesive member to be fitted to the perimeter of the flange of the tubulation tubing; placing the tubulation tubing and the adhesive member on a display panel having a vent hole in such a manner that the end face of the flange of the tubulation tubing contacts the display panel and the vent hole is covered with an opening of the tubulation tubing; and holding the tubulation tubing by pressing the flange of the tubulation tubing to a face of the display panel with use of a pressing tool and heating to a temperature at which the adhesive member softens, thereby bonding the flange of the tubulation tubing to the display panel by fusion of the adhesive member.
According to the present invention, the tubulation tubing having, at one end, the flange with a substantially flat end face and the ring-shape adhesive member to be fitted to the perimeter of the flange of the tubulation tubing are prepared. The tubulation tubing and the adhesive member are placed on the display panel, and the tubulation tubing is held by pressing the flange of the tubulation tubing against the display panel face with a pressing tool. Therefore, the pressing tool does not contact the adhesive member directly, which prevents the adhesive member such as glass from adhering to the pressing tool, for example, a clip.
Further, the tubulation tubing having the adhesive member already fitted to the periphery of the flange is placed on the display panel with the end face of the flange of the tubulation tubing contacting the display panel, and the tubulation tubing is held by pressing the flange of the tubulation tubing against the display panel face with the pressing tool. Therefore, the melted adhesive member does not enter the inside of the tubulation tubing. Also, since the pressing force of the clip can be strengthened, the inclination of the tubulation tubing by external force can be suppressed.
These objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.